Electrical testing system.



H. P. CLAUSEN & c. L. GOODRUM.

ELECTRIBAL TESTING SYSTEM.

V APPLICATION FILED DEC.21.1916- 1,23'7,;47& Patented Aug. 21, 1917.

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HENRY P. CLAUSEN, OF MOUNT VERNON, AND CHARLES L. GOODRUM, Q YORK,

I 'N. Y. ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEWYORK,

N. Y.,' A. CORPORATION OF NEW YORK.

ELECTRICAL TESTING SYSTEM.

Specification of Letters Patent. Patented Aug. 21, 1917.

Application fil ed December 21, 1916. Serial No. 138,169.

T 0 all whom it may concern:

. Be it known that we, HENRY P. CLAUSEN and CHARLES L. GOODRUM, citizensof the United States, residing at Mount Vernon, in

the county of Westchester and State of New.

York, and at New York, in the county of New York and State of New York,respectively, have invented certain new and useful Improvements inElectrical Testing Systems, of which the following is a full, clear,concise, and exact description.

This invention relates to electrical testing systems, and particularlyto that class of ardconditions of a certain nature which areencountered.

After a connection has been established between two subscribers, and thecalling subscriber has abandoned the call, but the called subscriber hasfailed to replace his receiver on its hook, the connector switchconcerned.

in the connection, as well as the called line, are said to be in anunstandard condition. It is necessary to relieve, or remedy, thiscondition as soon as possible. Periodic manually conducted tests fordetecting such held connectors are unsatisfactory, and result in adetriment to the service. 7

Automatic routine tests may be performed with the apparatus and meansdisclosed herein, with the result that, in most cases, the unstandardcondition will be detected and remedied before a complaint can belodged.

In the drawings, the part above the broken line diagrammaticallyrepresents the cir cuits of a well-known connector switch, and that partbelow the broken line diagrammat:

ically represents an arrangement of the testing and recording means.

In the preferred form of the invention there is provided a testing meanswhichis responsive to a changed electrical condition at one point onlyin the circuit of theCOnnector switch. If, during a routine test, anunstandard condition is encountered, the re sponse of the testing meansplaces a how ler tone on the talking conductors of the held connectorswitch, which is intended to sumnoon the responsible party. Ifthisparty,

in response to such a summons, replaces his receiver on its hook, norecord of the un standard condition is made. If,fonthe other hand, theunstandard" condition is not remedied 'within a predetermined length oftime such condition is recorded, and the testing device is advanced intoassociation with the next connector swltch.

There are three conditions in whichsuch an automatic connector switch asis shown in that part of the drawing above-the broken line may be foundduring an automatic routine test. It may be found: first, in an idlecondition, second, 'in abusy condition, and

third, in a condition created by the abandon.- ment. of the call bythe'calling party, where the called party has failed to replace his jreceiver on its hook.

In the idle condition, the-switch will be substantially as shown in thedrawing, that is, all side-switch arms will be in first position, andall magnets and relays de'elnergi'zed and the off-normal switch open.

With such a switch in a busy condition, the line relay LE under controlof the calling line, will be energized; the slow relay 10,

controlled by the line relay LR, will be energized; relay 5,,whosefunction it is to extend the talking conductors through to the calledparty, will be energized, and the relay LE controlled by the calledparty,*will be energized.

These conditions may best be understood by the following shortdescription of the operation of such switch in extendinga connectionfrom the calling line to a called line.

Let it be assumed that the switch shown has been seized by a, selectorswitch in the. well-known manner. A path of low resist-' ance is therebycompleted between conductors 1 and 2, which results in the establishmentof a circuit from ground, battery, theleft-hand winding of relay LEthe'normal contact and inner lower armature of line relay LR conductor1, the path of low resistance mentioned, conductor 2, the innermostupper armature and normal contact of relay LE theright-hand winding ofline relay 'LR and thence to ground. RelayjLR at tracts its armatureand: establishes a circuit from ground, armature-and a-lternatecontactof relay LE the Winding of slow release relay 10, to battery andthenceto ground. Slow release relay 10 is energized in this circuit andcompletes a connection from ground, contact and outermost armature ofrelay 10, test wire TVV, and thence over well- I known circuits, to thewinding of a relay in the line switch concerned inthis connection (notshown), to battery, and thence to ground.

The calling party now dials to transmit a series of impulses, theseimpulsesbeing short openings of the path of low resistance spoken of.Line relay LE in response to such impulses, causes its armature torapidly vibrate Magnet 11, however, is slow to release, and

does not respond to'the separate impulses transmitted through itswinding and, therefore, remains energized until after such impulseshave" ceased. On the other hand, magnet PM,being 'fas't,'responds toeach separate impulse, and steps the brushes of the connector switch tothe terminals of'the de sired group in the wellknown'manner.

The energizationof the slow release relay 11 results in theestablishment of a circuit from ground, armature and contact of relay11, the winding of relay 6, to battery and thence to ground. Relay 6controls the movement of the side-switch arms, and, upon itsenergization, moves the side-switch arms into their second position.This occurs after the sending of this first series of impulses inresponse to the retraction of the armature of relay ll.

The subscriber now dials a second time 7 and the consequent vibration ofthe armature of line relay LE between its normal and its alternatecontacts results in the transmission of impulses through the cir-' cuitdescribed, except in this case such impulses travel through theWlDCllIlg of the secondary magnet SM mstead of the primary magnet PM,from thence'through the side-switch arm 4 in the second position, tobattery and ground, over the circuit previously traced. -Under controlof the secondary magnet SM, the brushes 8 and 9 are driven into contactwith the terminals of the desired line.

The energization of relay 11 during the I sending of this, second seriesof-impulses energizes the relay 6 in the manner hereto-- fore described,and upon its dee'nergization at the end of the series of impulses, thesideswitch arms 8 and 4 are moved into third position. A circuit isthereupon established from ground, the side-switch arm 8,1the armatureand contact of relay 6, winding of relay 5 to battery and ground. Relay5 attracts its armatures and thereby extends the talking conductors ofthe connector switch to the brushes 8 and 9, and thence to theconductors of the called subscribers line.

At the same time a circuit is established from ground, interrupter Iwinding of realternate contact and armature of relay 7,

upper armature and contact of relay 5, the brush 9, through theconductors and signaling apparatus of the called subscribers substation,to the brush 8 contact and lower armature of relay 5, lower armature andalternate contact of relay 7 toa source'of ringing current. Through thiscircuit the bell of. the called subscribers substation is oper ated.

lVhen', in response to the summons of his telephone bell, the calledsubscriber removes his receiver from its hook, and when the interrupterI is in such a position that the relay 7 is deenergized, a circuit isestablished from ground, battery, the upper winding of relay LE theupper normal contact and armature of relay 7, upper armature and contactof relay 5, brush 9, through the lines and apparatus of the calledsubscribers substation, tothe brushS, contact and lower armature ofrelay 5, lower armature and nor mal contact of relay 7, lower winding ofrelay LR to ground. The relay LE is energized in this circuit andreverses the polarity of the current traveling over the conductors 1 and2 of the calling subscribers substation in a manner and for a purposewell-known in the art. At the same time relay LR completes a circuitfrom ground, contact and outer armature of relay 10 test wire TlV,outermost upper armature of relay LE the winding of relay 13, tobattery, and thence to ground. Relay 13 is energized in this circuit.and attracts its armatures and opens at its uppe armature and contactthe circuit for relay 7. The energization of relay 18 also results inthe establishment of a locking circuit for itself from ground at thecontact and outermost armature of relay 10, contact and, lower armatureof relay 13, winding of relay 13, to battery and thence to ground.

The relay 7 is not, therefore, again energized and the talkingconductors ofthe con- "nector switch are maintained in steady connectionwith the brushes 8 and 9, whereby a conversation between the calling andthe called subscriber may take place.

Suppose now that both subscribers hang up their receivers. Theconnection set up and switch, shown herein, will be ended and theswitches concerned will return to normal in the well-known manner. Inthis case, the line relays LR and LE under the control of the twosubscribers, as heretofore described, will be dee'nergized. The groundon the test wire TVV, at the contact and outermost armature of relay 10,under control of relay LE will be removed, thereby allowing the lineswitch and other selector switches to release. At the same time a groundwill be placed on the release magnet 15 through a circuit extending fromground,

the armature andnormal contact of relay LE innermost armature and normalcontact of relay v1O, the oif-normal contact12, the lowermost armatureand contact of relay LE the windingof magnet 15, to battery and thenceto ground, whereupon this connector switch will be released.

If, on the other hand, the called subscriber fails to replace hisreceiver on its hook, then only relay LE will retract its armature andthe ground placed on the circuit just described will have to travelthrough the winding of relay 14 in series with the-windand thence'toground. This ground also extends through thelower armature and contactof relay 13 to the test wireTW, thus holding the line switch andselector switches concerned in this connection.

The third condition in which this connector switch may be found is,therefore, apparent from the foregoing description. The ground exists onthe circuit between the ofi-normal contact 12 and the winding of relay14. Relay 14 and line relay LE are still energized under the control ofa called subscriber. i I

Referring now especially to'the partof the drawing below the brokenline, it will be seen that from each connector switch three,

conductors are led to afset of terminals t,

t and t the terminals t and leading to is energized. Therefore, thesequence switch 18 will pass all of its positions'as just de-' theconductors which extend through the armatures and contacts of relay 5'to the established through the connector brushes 8 and 9; the terminal tleading to the point in the circuit of the connector switch which, fromthe previous description, will be recognized as being connected to theground only when the condition for which the test is being carried onoccurs.

There is a set of brushes 6, b and b which are arranged to travel overand make contact with the terminals t, t and t These brushes are drivenfrom one set of terminals to another by a stepping magnet 16, and extendthe circuits from the connector switch to the testing apparatus throughthe contacts and armatures of relay 17.

The operation of this testing apparatus may be described as follows: I

A hand switch H is provided for putting such apparatus into operation.The lefthand member of this switch provides a circuit from groundthrough the interrupter I to the winding of the motor magnet of thesequence switch 18, to battery and ground. Through this: circuit thesequence switch is stepped forward one step at a time.

Suppose that the brushes 7), b and b first come in contact with a set ofterminals t, t and 6 connected to an idle connector switch. Since noground appears on the terminal If, neither relay 19 nor 20 will beenergized in any position of the sequence switch during thiste'st. Asposition 1 is reached a circuit will be established from ground,battery, right-hand member of switch I-l, sequence switch contact 30,winding of relay 17, normal contact and armature of relay 21, to ground.Relay 17 will be energized in this circuit in position 1 only, and willattract its armatures 22, 23 and 24. When position 2 is reached acircuit will be established from ground, battery, the right-hand memberof hand switch H, sequence switch contact 31, winding of relay 21, thenormal contact and outermost armature of relay 19 to ground. Relay 21 isenergized in this sequence switch contact 32, the right-hand member ofhand switch H tobattery and thence to ground. Stepping magnet 16advances the brushes 5, b and 79 into contact with the set of terminalsconnected with the next switch to be tested.

Let us assume that in thiscase the connec tor switch is involved in athrough connection from acalling subscriber to a called subscriber. N0ground in this case will be connected to the terminal-t since the relay10 scribed, and the stepping magnet 16, will advance the brushes Z), tand b to the next set of terminals to be tested,

We will now assume that the connector switch is held by a calledsubscriber on a connectionwhich has been abandoned by the callingsubscriber. A ground will be placed on terminal t from the armature andnor-.

mal contact of relay LE inner armature and normal contact of relay 10,olf-normal switch 12 to t.

I i-position 1 of the sequence switch 18 relay 17 will be energized asheretofore described. A circuit will also be established between theground at terminal 't described, will now be found open at the outermostarmature and contact of relay 19; hence relay 17 will maintain itsarmatures attracted throughout positions 1 to 12, inclusive, asindicated at sequence switch contact 30. As position 6 is reached acircuit is established leading from the middle armature and contact ofrelay l9, condenser C, sequence switch contact 35, armature 22 andassociated contact of relay 17, brush Z2 terminal 6 normal contact andupper armature of relay 7, the upper armature and contact of relay 5,bush 9, through the circuit provided by the called subscriberssubstation apparatus, brush 8, contact and lower armature of relay 5,lower armature and normal contact of relay 7, terminal 25 brush 6contact and armature 23 of the relay 17, sequence switch contact 34,contact and innermost armature of relay 19, secondary winding oftransformer T, and thence to the middle armature of relay 19. Theprimary winding of transformer T provides a source of alternatingcurrent of such high fre quency that a current induced in the Secondaryand flowing through the. circuit just described will so actuate thereceiver of the called subscribers telephone set that a howl will beproduced therein. This is designed to attract the called subscriber sat-.

tention, who may ceiver on its hook.

Should this happen the connector switch will be restored to its idlecondition, whereupon relay 19 will be deenergized and in turn the relay21 will be energized. The attracthereupon replace the retion of itsarmature by relay 21 removes, through the deenergization of relay 17the. testing apparatus fromconnection with theconnector switch and Whfinthe sequence As position 2 is reached the circuit for relay21,.heretofore.

switch--18 finally arrives at the thirteenth position, thebrushes b, band b are advancedv to a new set of terminals.

If, on the other hand, the subscriber should not replace the receiverupon its hook before position 12 of. the sequence switch 18 is reached,then accircuit will be provided from. ground at terminal 6.. through the0rd of the condition in which the connector switch under test is found.When, an instant later, sequence switch 18 arrives in the thirteenthposition, stepping magnet 16. is

energized, as heretofore described, and ad vancesthe brushes, I27, 6 andb to a new position. 7

What is claimed is:

1. In an electrical testing system, an arrangement for detectingunstandard conditions in an automatic selective switch, comprising atesting means responsive to an electrical, condition on the release wireof such automatic selective switch indicating an unstandard condition, asingle link conductor extending between said release wire and saidtesting means, automatic means for associating said testing means withsaidconductor, and means controlled by said testing means for indicatingsuch unstandard condition.

2. An arrangement for detecting and recording. an unstandard condltlonin an automatic selective switch comprising a single relay responsive toa potential indicating an unstandard condition, a signaling apparatus'controlled by said relay for apprising the responsible person ofsuchunstandard condition, recording means responsive to a potentialindicating an unstandard condition, and means for preventing theoperation of the recording means in case the unstandard condition 1seliminated in response to theoperation of such signaling apparatus.

3. An electrical testing system for detecting unstandard conditionscreated in an automatic selective switch through the failure of a calledparty to replace his receiver on its hook after the calling party'hasabandoned the call, comprising testing, means .responsive to anelectrical condition at one point in, the .circuit'of such a selectiveswitch means for preventing the operation of said recording means.

4:. An electrical testing system for detecting and recording unstandardconditions in an automatic selective switch created through the failureof a called party to properly manipulate the apparatus connected withsaid switch, comprising testing means responsive to a changed electricalcondition at one point in the circuit of such a selective switchindicating an unstandard condition, recording means also responsive tosaid changed electrical condition, signaling means controlled by saidtesting means for apprising the responsible party of such unstandardcondition, and means controlled by said testing means for preventing theoperation of said recording means responsive to the proper manipulationof said apparatus connected with said switch in response to saidsignalingmeans.

5. An arrangement for detecting an unstandard condition in an automaticselective switch, which is used in establishing telephonic connectionand which unstandard condition is created by the improper manipulationof subscribers apparatus, comprising contacts connected to the talkingcircuits of said switch and a contact connected to the release circuitof said switch, testing means responsive to a changed electricalcondition in such release circuit indicating an unstandard condition ofsaid switch, automatic means for associating said testing means withsaid contacts, and means controlled by such testing means to indicatethe existence of an unstandard condition.

6. An arrangement for determining unstandard conditions in an automaticselective switch used for establishing telephonic connection, comprisinga single contact connected to the release circuit of said switch,testing means responsive to a potential on such release circuitindicating an unstandard condition, and means for automatically andsuccessively associating such testing means with such contacts and withsaid testing conductor.

7. An arrangement for detecting and recording an unstandard condition inan automatic switch used for telephonic connection, comprising a singlecontact connected to the release circuit of said switch, contactsconnected to the talking circuits of said switch, testing meansresponsive to a potential on said release circuit indicating anunstandard condition, a signaling means controlled by said testing meansfor apprising the responsible party of said unstandard condition, meansfor recording said unstandard condition, and means under control of saidresponsible party for rendering inoperative said recording means.

In witness whereof, we hereunto subscribe our names this 19th day ofDecember A. D.,

HENRY P. CLAUSEN. CHARLES L. GOODRUM.

Gopies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

